|
Search: id:A131658
|
|
|
| A131658 |
|
For n positive, put A_n(z)= sum_j (nj)!/(j!^n) *z^j, B_n(z)= sum_j (nj)!/(j!^n) *z^j * (sum_{j<k<=jn} (1/k)) and let u(n) be the largest integer for which exp(B_n(z)/(u(n)A_n(z))) has integral coefficients. The sequence is u(n). |
|
+0
4
|
|
| 1, 1, 1, 2, 2, 36, 36, 144, 144, 1440, 1440, 17280, 17280, 241920, 3628800, 29030400, 29030400, 1567641600, 1567641600, 156764160000, 49380710400000, 217275125760000, 1086375628800000, 1738201006080000
(list; graph; listen)
|
|
|
OFFSET
|
1,4
|
|
|
COMMENT
|
Different from A131657 and A056612.
|
|
REFERENCES
|
Christian Krattenthaler and Tanguy Rivoal, On the integrality of the Taylor coefficients of mirror maps, preprint, arXiv:0709.1432.
|
|
LINKS
|
Christian Krattenthaler, Table of n, a(n) for n = 1..40
|
|
FORMULA
|
A formula, conditional on a widely believed conjecture, can be found in the article by Krattenthaler and Rivoal cited in the references: see Theorem 4 and the accompanying remarks.
|
|
CROSSREFS
|
Cf. A007757, A056612, A131657.
Sequence in context: A074127 A024176 A056612 this_sequence A131657 A059523 A038623
Adjacent sequences: A131655 A131656 A131657 this_sequence A131659 A131660 A131661
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Christian Krattenthaler (Christian.Krattenthaler(AT)univie.ac.at), Sep 12 2007, Sep 30 2007
|
|
|
Search completed in 0.002 seconds
|
